CODEWITHSUNDEEP
javascriptarraysreactjspayload
CatGirl19
CatGirl19

Reputation: 209

How to return a boolean if array index values are equal to a x & y values

Is there a way to check if array this.state.allBooks contains both id:552 and name:'book2' in the same index and return either true or false... I want to avoid using a for loop if possible.

// Array this.state.allBooks 
O:{id:133, name:'book1'}
1:{id:552, name:'book2'}
2:{id:264, name:'book3'}

previously I've done something similar to the below code, but since array this.state.allBooks has an id and a name I'm not sure what approach to take.

let boolValue = this.state.allBooks.includes(/* check if it includes a single value*/)

//Desired output 
// 1.0) Does this.state.allBooks include both id:552 and name:'book2' in the same index ? 
// a)   if yes return true ... should be yes since both id:552 and name:'book2' are part of the same index '1'
// b)   if no return false

Upvotes: 0

Views: 743

Answers (4)

Yunus Emre
Yunus Emre

Reputation: 125

Using javascript's array method of some will return a boolean if any of the elements inside the array pass the test given to the method. Here this code iterates over the array checks if any element's id is 552 and name is 'book2'. If it finds any element to pass this test it will return true otherwise false.

// Array this.state.allBooks 
const books = [{id:133, name:'book1'}, {id:552, name:'book2'}, {id:264, name:'book3'},]

let isObjIn = books.some(book => book.id === 552 && book.name === 'book2');
console.log(isObjIn); // logs true

Upvotes: 0

Shashan Sooriyahetti
Shashan Sooriyahetti

Reputation: 878

Hi you can use map function,

let state:any = {};
let boolValue:boolean = false;
state.allBooks = [
  {id:133, name:'book1'},
  {id:552, name:'book2'},
  {id:264, name:'book3'}
];
state.allBooks.map(e=>{
  if(e.id == '552' && e.name == 'book2'){
    boolValue = true;
  }
});
console.log(boolValue)

here is a working example link

Upvotes: 0

peach
peach

Reputation: 747

I think you can just use JavaScript's method some of the array class. Some will return true if any of the elements in the array match the given predicate so the following code should do the trick:

let boolValue = this.state.allBooks.some(bookObject => bookObject.id === 552 && bookObject.name === 'book2');

Upvotes: 3

Terry
Terry

Reputation: 66103

You can use Array.prototype.find to search for the entry. However, do note that internally the implementation of Array methods that involves searching and filtering always involve some kind of for loop anyway.

const data1 = [{id:133, name:'book1'},{id:552, name:'book2'},{id:264, name:'book3'}];
const found1 = data1.find(({ id, name }) => id === 552 && name === 'book2');
console.log(found1);    // { id: 552, name: 'book2' }
console.log(!!found1);  // true

// Let's mutate the entry so it will not be found, for testing
const data2 = [{id:133, name:'book1'},{id:999552, name:'xxxbook2'},{id:264, name:'book3'}];
const found2 = data2.find(({ id, name }) => id === 552 && name === 'book2');
console.log(found2);    // undefined
console.log(!!found2);  // false

Upvotes: 0

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